The present invention relates to liquid storage containers for manually dispensing liquids such as cleaning solutions for contact lenses, and more particularly relates to dispensing nozzles on containers for liquid which must be stored in sterile condition.
Liquids, for example, solutions for cleaning and conditioning contact lenses, have typically been stored in manually squeezable bottles from which the user can repeatedly dispense the stored liquid. These liquids must be uncontaminated by microorganisms such as bacteria. Accordingly, expensive bacteriacidal agents have sometimes been included in liquid formulation, as for example, in saline formulations for cleaning contact lenses. Furthermore, the squeezable dispensing bottles have sometimes been provided with nozzles including filter membranes which are permeable to the dispensed liquid as well as being permeable to the air which must be aspirated through the nozzle to replace the dispensed liquid. These filter membranes are also impermeable to bacteria in order to prevent the aspirated air from carrying bacteria into contact with the stored solution, so that the solution is maintained in sterile condition for repeated dispensing. However, filter membrane materials which are sufficiently hydrophilic to permit permeation of the saline solutions often permit retention of the saline on the filter so that the retained solution increases the resistance of the filter to passage of the aspirating air. The partially obstructed flow of aspirating air not only retards the expansion of the squeezed bottle wall, but also impedes a subsequent squeezing of the bottle when a demand for large quantities of the solution must be dispensed.
In accordance with this invention, a nozzle assembly provides accelerated air aspiration of the squeezed liquid dispensing bottle for improved convenience to the user, particularly in repeated dispensing of the solutions for contact lenses.